Loud speaking wireless amplifier



April 26, 1921;

J. R. SHOWERS LOUD SPEAKING WIRELESS AMPLIFIER Filed @1124. 1922 Patented Apr. 26, 1927.

PATENT OFFICE.

JOSEPH RALPH SHOWERS, OF SHELBYVILLE, INDIANA.

LOUD SPEAKING WIRELESS AMPLIFIER.

Application filed April 24,- 1922. Serial No. 556,203.

My invention relates to loud speaking amplifiers for wireless telephones or telegraph receivers, and the object of the invention is to so amplify the weak vibrations of such a receiver not only so that the main sounds are clearly and distinctly heard, but that the higher tones or shorter and more rapid vibrations shall also be distinctly heard, as well as over tones.

To this end I construct my amplifier as a continuous wooden horn from thirty to thirty-six inches long, without any freely movable parts, from one end to the other yet not rigid, with an internal bore of gradv ually increasing diameter, and the wireless receiverdirectly connected to and vlbratable with thevsmall free end of the conduit.

I I am aware that in phonographs the movable tone arm, the amplifying block and horn have been made of wood of such thickness that these parts shall not vibrate, and like these constructions have found an advantage in the quality of the tone reproduced when using wood, but in using such a phonograph construction with difierent wireless apparatus, the amplification was no better than that given by the various ampliliers now on the market.

I then set about to solve the problem of 7 getting better amplification, having first satisfied myself that wood, or mainly wood, was the most satisfactory material, and from experimenting with wooden talking machine construction, I discovered that for wireless reproduction the conduit for the reproducer was not gradual enough, and also that better results would be obtained if the entire conduit was supported at as few points as possible, so as to allow that portion which corresponds to the tone arm of a phone graph to be entirely free to vibrate bodily, t e wireless receiver being supported on its free smaller end. i

I am, of course, aware that wooden wind horns, such as oboesand the like, using reeds or, other sounding means, have long existed,

a block of wood 5, conveniently built u of so several thicknesses of board, each a out three-quarters of an inch in thickness.

This block has a continuously widening sound passage or chamber 6 from its upper smaller end to its lower wider end, whichoa latter gradually Iner es into a rectangle at 7. This chamber 6 wi l, for convenience, be called the amplifying chamber, and is of ils-ghape, i. e. it makes a complete turn of The block 5 where it is secured to the top 4 has the joint reinforced by cleats 8.

Bi idly secured in the smaller end of the cham er 6 by gluing or otherwise, is a wooden tube 9 having a bore tapering from its larger end at the block 5 to its smaller free end, to which is connected the wireless receiver 10 of any suitable type.

Conveniently, the thimble 11 of this receiver has socket connection in the smaller end of tube 9, and is 'frictionally held or otherwise iastened therein. A .block 12,- to prevent accidental removal of the receiver, fits close to the receiver 10, but is not connected to it, so that the receiver and tube 9 shall be free to vibrate with respect to its opposite end secured in the laminated block 5, nearthe point of connection of the block 5 and top4 of the casing.

Extending from the lower rectangular end 7 of the am lifying chamber 6 is a horn consisting of thick wooden sides 13, secured i at their-smaller ends to the block and reinforced at the joint by corner blocks or cleats 14 on their outside. These sides are covered by curved veneer or sheet metal forming the top and bottom 15 and 16 of the horn portion, and-are secured to the upper and lower edges of the heavier sides 13 of the horn and reinforced where they join block 5, with corner cleats 14*. The sides 13 of the horn are bevelled at 17 and extend to the front corner posts 1.8 of the casing and abut against a bead 19.

The veneers l5 and 16 extend to the upper and lower rails 20 and 21 respectively of the casing, and their edges are covered by beads or finishing strips 22 and 23. The larger horn end may thus have slight movement as it is not rigidly secured to the corner posts and rails, while the two veneers will, in addition, be free to vibrate at their own period as resonant elements.

Thus it will be seen that the entire wooden conduit is free to oscillate or vibrate about the substantially single point of support where the block 5 joins the top 4, and the entire horn is thus suspended from or supported from the top of the case.

The movement due to vibration at the large end of the horn is very sli ht, as is also the vibration of tube 9, nevert eless the construction herein set forth solves the problem of loud speaking wireless amplification and users thereof have expressed universal satisfaction and preference for the results obtained.

The electrical cord 24 passes from the receiver 10 to the side of the block 5 and out of the casing throu h an insulating eyelet 25 and terminates in the customary plug contact 26 for plugging in to the wireless receivmg set.

I have discovered that the tube 9 must be longer than a tone arm on the customary talking machine, and must have a more gradual taper. The so called amplifying chamber 6 when reversely bent as shown should have a bend of 180 and gradually enlarge without any restrictions, and the whole tone conduit from the receiver 10 to the large end of the horn shall continuously increase in cross-sectional area.

The tube 9 must be free to vibrate in any case, as this is of more importance to proper results than if the large end of the horn be revented from vibrating. Of particular importance is the fact that there shall be no air openings in the conduit and no loose joints between tube 9 and the block 5, and between block 5 and the horn, otherwise the over tones will be lost, and some of the high tones.

The tube 9 must be from nine to twelve inches long, and the inside passage have a diameter from one-half to three-quarters of an inch at the smaller end, and from one inch to one-and-one-half inches at the larger end where it joins block 5.

I claim- 1. A loud speaking wireless amplifier comprising a continuous imperforate conduit free from parts movably joined together and continuously widening from one end to the other, means to suspend and hold thejconduit against bodil movement at a point between its ends, t e smaller end extendin from the held portion of the conduit and being adapted to hold a wireless receiver that vibrates with the vibrations of said smaller conduit end.

2. A loud speaking wireless amplifier, comprising a continuous, radually widening imperforate conduit, cc of movable parts, consistin of a tapering tube adapted to hold a wire ess receiver; a block havin an amplifying chamber and to which said tube is rigidly connected at one end and a horn portion to which said block is rigidly connected; and means for supporting and holding the block and amplifying chamber against bodily movement, said tube, block and horn forming a continuously taperin sound passage, whereby both the tube an the horn are supported stationarily but are permitted to vibrate during sound transmission in' rhythm to the sound waves'transmitted..

3. A loud speaking wireless amplifier comprising a casin a continuously ta ring and substantially rigid wooden condi nt therein consistin of a tubular portion, an amplifying cham er cut in a block of wood and making a reverse turn and a horn portion all connected in-series, said block being secured only at its top and narrower portion of the chamber to said casing and said horn having opposed resonating veneer walls.

4. A. loud speaking wireless amplifier comprising a casing, a continuous unbroken wooden air conduit gradually tapering from end to end and having a reverse bend between its ends, means to secure said bent portion to said casing and thereby leave the ends free to vibrate, the smaller and of said conduit being adapted to hold a wireless recelver.

5. In a loud speaking wireless amplifier, a wooden sound conduit free of movable parts and comprising a tapering thick-walled tube, a block having a reversel bent passage therein to the smaller end of which the larger end of said tube is rigidly secured, the passage in said block being circular at one end and gradually increasing in diameter and changing to rectangular shape at its lar er end, a horn portion rigidly secured to sai larger end, said horn portion havin opposed resonating walls, and means to hold said block at one point to unit free vibration of said tube, the am and of said tube being constructed to receive and hold a, wireless receiver.

6. A loud speakin wireless amplifier comprising a. continuous y widening imperforate 5 wooden conduit free of arts movable relatively to one another an means to suspend.

and hold said conduit 9. inst translation at :1V point between the en of the conduit 

